A conventional scalpel used in the healthcare industry includes a metal handle and a disposable blade that is mounted on the handle prior to use, and removed after use. The process of mounting and dismounting of the blade is a difficult and dangerous procedure as it exposes the medical practitioner to potential injury from the exposed blade and contamination due to blood that may be present on the blade. Further, sharps injuries may also occur during an operation as the surgeon passes the exposed scalpel to a colleague.
An example of a safety scalpel with a releasable blade cartridge is described in U.S. Pat. No. 5,938,676 (Cohn). Although Cohn describes a slidable shield which is slidable to cover the blade when the scalpel is to be disposed, a user is required to push the shield in a forward direction to cover the blade. This action is counter intuitive because it differs from a conventional direction of use in conventional box cutter devices. U.S. Pat. No. 8,567,072 (Yi) describes another example of a safety scalpel with a detachable blade cartridge. The safety scalpel in Yi is adapted to extend and retract by pushing downward on the button and then sliding along the shield to change its position.
The blade cartridge with an extended blade may be inadvertently detached and this may cause potential injury from the exposed blade. To avoid the danger of an exposed blade when the blade cartridge is detached for replacement, some prior art safety scalpels include arrangements in which the blade is self-retractable into the handle or the blade cartridge. Such self-retracting safety scalpels are continually biased towards the retracted position and into the handle using a retractable blade holder by having spring mechanisms arranged to bias the blade holder rearward. However, such self-retracting safety scalpels still require the user to initiate an action to retract the blade. If the user forgets to retract the blade and proceed to remove the blade cartridge with the extended blade, potential injury will still be caused during removal of the blade cartridge.